Safety fill flow control well apparatus

ABSTRACT

Apparatus for controlling the flow of fluid into a casing string as the string is being lowered in a well. A valve in the casing string permits the casing string to fill at an adjustable rate and shuts off flow at a predetermined high flow rate. Frangible means releasably connects the valve to the casing string. A twoplug cementing technique is usable with this apparatus.

United States Patent [72] Inventor Juan A. Garcia Corpus Christi, Tex.[21] Appl. No. 878,508

[22] Filed Nov. 20, 1969 [45] Patented Nov. 2, 197 1 [73] Assignee EssoProduction Research Company [54] SAFETY FILL FLOW CONTROL WELL PrimaryExaminerlan A. Calvert Attorneys--Thomas B. McCulloch, Melvin F. Fincke,John S.

Schneider, Sylvester W. Brock, .lr., Kurt S. Myers and Timothy L.Burgess ABSTRACT: Apparatus for controlling the flow of fluid into acasing string as the string is being lowered in a well. A valve in thecasing string permits the casing string to fill at an adjusta ble rateand shuts off flow at a predetermined high flow rate. Frangible meansreleasably connects the valve to the casing string. A two-plug cementingtechnique is usable with this apparatus.

PATENTEDN 2 3,616,851

* llil/ INV/CN'I'HR.

JUAN A. GARCIA, WAMMI ATTOR NEY.

SAFETY FILL FLOW CONTROL WELL APPARATUS BACKGROUND OF THE INVENTION runa string of pipe in the borehole and then pump cement down the pipestring. The cement flows out the bottom of the pipe string and upwardlythrough the annular space between the outside of the pipe string and thewall of the borehole. When the cement hardens, the pipe string is firmlysecuredin the well bore and further well operations may be carriedout.When lowering the pipe string in the borehole, it is desirable to fillthe pipe string with fluid gradually to reduce the pressure differentialbetween the interior and exterior thereof. Further, as the pipe stringis being lowered in the borehole, the well might start to come in, andif this happens, the formation pressure may force fluid into the bottomof the pipe string so rapidly that fluid would blow out the top of thepipe string. Such a blowout may be prevented by shutting off flow offluid into the bottom of the pipe string and applying pressure toovercome the fonnation pressure.

SUMMARY OF THE INVENTION In accordance with the teachings of the presentinvention, apparatus for controlling the flow of fluid into a pipestring as the pipe string is lowered in a borehole is arranged in thelower end of the pipe string to permit the pipe string to fill at anadjustable rate and to shut off upward flow of fluid at a predeterminedhigh flow rate. This apparatus includes a valve housing having a flowpassage therethrough and a valve seatadjacent to such passage. A valveelement, retained or supported on a sleeve attached to the valvehousing, is movably arranged in the passage for seating on the valveseat. Biasing means is arrangedon the valve element for urging the valveelement downwardly away from the valve seat. A stop is positioned on theinterior wall of the pipe string to prevent upward movement of the valvehousing and a frangible means initially connects the valve housing tothe wall of the pipe string to prevent, until fractured, downwardmovement of the valve housing.

The pipe string with the flow control apparatus positioned in it islowered in the well borehole. As it is lowered, fluid passes throughopenings in the pipe string below the flow control apparatus andupwardly through the valve housing passage at a rate that is adjustablein accordance with the velocity of the fluids passing through suchpassage. If the well comes in while the pipe string is being run intothe hole, flow into the well pipe string is shut off by the valveelement being forced upwardly to seat in the valve seat. The BOP ramsare closed on the pipe string, and conventional well-killingproceduresmay then be continued. In cementing the well pipe in the wellbore using a two-plug technique, the forward and rear plugs, togetherwith the cement in between are pumped down the well pipe until theforward plug contacts the valve housing which causes the frangibleconnection between the housing and the well pipe to shear and the valvehousing and its components are carriedto the bottom of the pipe string.The cement flows through the openings in the pipe string and into theannulus surrounding the pipe string.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a cross-sectional view ofthe lower end of a pipe string containing theflow control apparatus ofthe invention, as the pipe string is lowered in a well bore;

FIGv 2 is a view similar to that shown in FIG. 1 illustrating the startof a cementing operation with the pipe string on the bottom of the wellbore;

FIG. 3 is a view similar to that shown in FIG. 1 illustratirig thecementing operation as it is being completed;

FIG. 4 is a more detailed view of the valve element in the flow controlapparatus; and

FIG. 5 is a view taken on lines 5-5 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS ward movement of a valvehousing 13 arranged in and connected to pipe string 10 by shearpins 14which engage a groove 14a formed on the outer surface of valve housing13.

Suitable 0-ring seals 15 seal off the space between the outer wall ofhousing 13 and the inner wall of pipe string 10. The interior of housing13 has a passageway 16 therethrough and a conical surface 17 thereofforms a valve seat. A valve stem 18 having a valve element 19 at itsupper end extends through the lower end 20 of housing 13 which hasopenings therein. A spring 21 surrounds valve stem 18 between the lowerend 20 of housing 13 and a plate 22 secured to valve stem 18. Spring 21urges valve stem 18 and valve element 19 downwardly away from valve seat17. As shown in FIGS. 4 and 5, the valve housing 13 is provided with avalve retainer sleeve 13a threadedly attached to the valve housing, asshown, to facilitate fabrication of the flow control apparatus and toprovide a means for adjusting the spacing between the valve element 19and theseat 17 before the pipe string 10 is run in the borehole.

In operat'iomwhen running pipe string l0 into borehole 9 as illustratedin FIG. 1, drilling mud in borehole 9 differentially fills cement'shoeII and pipe string 10 through openings 25 and passageway 16 in valvehousing 13, as indicated by the ar- 1 rows. Valve element 19 is normallybiased to the open position by spring 21. The opening through valvehousing 13 depends upon strength of spring 21 and velocity of fluidsmoving through passageway 16.'Thus, pipe string 10 fills with wellfluids at an adjustable rate while it is being lowered in borehole 9.Ifthe well comes in while pipe string 10 is being run into borehole 9 inthis manner, the velocity of flow causes valve element 19-to moveupwardly and seat on valve seat 17 against the bias of spring 20. Ramsare closed on pipe string 10 at the surface and well-killing proceduresare then carried out.

In cemeri'tirig pipe string 10 in borehole 9 after pipe string 10 islanded on the bottom of the borehole as illustrated in FIG. 2, a leadorfir'st (rubber) plug 26 is inserted in pipe string 10 followed by a'cement slurry 27 pumped down pipe string 10. Drilling mud in drillstring 10 is displaced through ports 25 in pipe string 10 and cementshoe 11. After a desired amount of cementslurry is pumped into pipestring 10, a follower or second (rubbeijplug 28 is inserted into pipestring 10 behind cement slurry 27. A displacement fluid 29 is pumpedinto pipe string 10 behind follower plug 28. Plug 26 engagesvalvehousing 13 and pump pressure from the surface pump causes shearpins14 to fracture and force valve housing 13 to the bottom of cemerit shoell where it lodges as illustrated in FIG. 3. Downward movement of plug28 displaces cement slurry 27 through side openings 25 into the annulusof the borehole surrounding pipestringIO displacing drilling mudupwardly to cement pipe string 10 in the borehole, as shown by thearrows.

Having fully described the apparatus, operation and advantages of myinvention, I claim:

1. Apparatus for controlling flow of fluid into a pipe string as saidpipe string is being lowered in a well comprising:

a pipe section having openings therein connectedto the lowermost end ofsaid pipe string;

a valve assembly arranged in said pipe section spaced above saidopenings in said pipe section including a housing having a flowpassagetherethrough and a valve seat therein, a valve element movably arrangedin said passage adapted to seat on said valve seat, a valve stemconnected to the underside of said valve element, a retainer sleevesurrounding said valve element and threadedly attached to the lower endof said housing for supporting said valve element below said valve seat,said threaded attachment permitting adjustment of the spacing betweensaid valve housing in an upward direction away from said openings; and

frangible means including shear pins connected to said pipe sectionreleasably connecting said valve housing to said pipe section, saidhousing being provided with a groove in which said shearpins areinitially located.

1. Apparatus for controlling flow of fluid into a pipe string as saidpipe string is being lowered in a well comprising: a pipe section havingopenings therein connected to the lowermost end of said pipe string; avalve assembly arranged in said pipe section spaced above said openingsin said pipe section including a housing having a flow passagetherethrough and a valve seat therein, a valve element movably arrangedin said passage adapted to seat on said valve seat, a valve stemconnected to the underside of said valve element, a retainer sleevesurrounding said valve element and threadedly attached to the lower endof said housing for supporting said valve element below said valve seat,said threaded attachment permitting adjustment of the spacing betweensaid valve element and said valve seat, and biasing means for urgingsaid valve element and valve stem downwardly away from said valve seat;sealing means arranged on said housing to seal off the space between theouter wall of said housing and the inner wall of said pipe section; astop arranged on the inner wall of said pipe section engaging said valvehousing to prevent movement of said valve housing in an upward directionaway from said openings; and frangible means including shear pinsconnected to said pipe section releasably connecting said valve housingto said pipe section, said housing being provided with a groove in whichsaid shearpins are initially located.